[Strat-Mangler]

Hmmmm,.. nevermind. Just noticed my mistake.

 

[Ripper2860]

Hello all. I am a recent Schiit Lyr 3 owner and possibly a contributor to the driving up of 6SN7 tube prices and for that I apologize. You folks here seem like a friendly and knowledgeable lot, so I thought I would pose my tube question here. I just purchased 2x Sylvania brown-base tubes, but don't really know a whole lot about them. A picture below and I'm hoping to get a tube identification and perhaps a sound profile. I think they are early true Chrome Domes, but I really don't know. It was an impulse buy and I'm steeling myself for the possibility it is a pair of junk tubes, but holding out that it might be a good buy.

Any input or thoughts would be appreciated.

Thanks!!

 

[gibosi]

These appear to be Sylvania-made chrome domes from the mid-1950's. However, these were manufactured for the US military, note the "WGT". While I can't tell from the pictures, they likely have an extra vertical support rod between the top and bottom micas and metal "umbrella" spoke spacers attached to the top mica. So they are different than the earlier civilian chrome domes.

They are certainly not "junk tubes".

 

[Ripper2860]

Excellent. Thank you for your quick response. Do you have any thoughts as to how they sound or a sound profile? Are these typically sought-after audio tubes or just vintage 'meh' tubes?

Again -- Thanks!!

 

[gibosi]

Many people quite like them. You can read some impressions here:

https://www.head-fi.org/threads/the-reference-6sn7-thread.117677/

 

[Ripper2860]

Once again -- thanks!!! Looks like I have some reading to do !!

 

[Ripper2860]

Here's another image that shows what appears to be an umbrella spacer and a support rod ...

Again -- THANKS!!!

BTW -- they have not arrived yet.. These pics are from the seller. I'll definitely remove all the stickers and labels.

 

[attmci]

Excellent. Thank you for your quick response. Do you have any thoughts as to how they sound or a sound profile? Are these typically sought-after audio tubes or just vintage 'meh' tubes?

Again -- Thanks!!

These are not sought-after 6SN7W or 6SN7A (as marked on the tube). I hope you don't spend a lot of $ on these tubes.

As Ken said, these are military version of 6SN7GTAs.

YES, you guys are driving up the price of all kinds of 6SN7GT. The $60 you paid are ok price. However, no, they won't touch the SQ of a real pair of KR VT-231. The 6SN7W/A is another story and much more $$$.

The photo of a pair of real 6SN7W/6SN7As are attached.

 

[Ripper2860]

Yeah, I knew these were WGTAs and not A or W, despite what the dynamo label says. I went with the etching on the glass as the final determination. From what I've read today, it seems the Syl Brown Base WGTA is still a nice tube, but certainly not at the same level as the A or W. I paid $60 for the pair, so hopefully it still represents a good value. If it meets or surpasses the 1940's Ken-Rad VT-231, I'll be a very happy camper!!

 

[Ripper2860]

However, no, they won't touch the SQ of a real pair of KR VT-231.

Ooooh. I've been coveting the metal base A and W since reading about them.

A bit disappointing that the WGTA's will likely not surpass the KRs. Don't get me wrong, I do love the KR's and already own 3 of the 1940's staggered black-plate KR JAN VT-231 tubes (clear and black glass), but I read about the wide soundstage of the brown base WGTA's and was hoping to get that and a bit more SLAM. Given that sometimes the gear the tubes are associated with impact their final sound, it'll be interesting how the WGTA's sound with the Lyr 3.

On another note: I did procure a Sylvania 6SN7W black base Tall Boy tube. I'm anxious to see how it does, as well. While it is not at the same level of praise as the metal base versions, the comments seem pretty favorable of the black base Tall Boy. Keeping my fingers crossed that it does not exhibit any microphonics or arc'ing as some say they are prone to doing. Hopefully a headphone amp is less demanding and less prone to these issues.

Thanks!!!

 

[Ripper2860]

Hello. My name is Richard and I'm a tube addict ...

I snagged a couple of strong and supposedly pretty well balanced Sylvania 6SN7GT tubes with an 052 (1950) year code. These are 2- hole 'Bad Boy' style (I know they're not real Bad Boys) and they have a raised bottom mica, and bottom getter chrome flashing, black base and green labeling with the classic 6SN7GT in a stop-sign logo on the glass. Do any of you fine folks have any additional info on this year. I seem to find a lot about Sylvie VT-321, W's, A's, 1950 Chrome Dome, and '52 GT's, but not much about this year GT. I can't seem to really discern on the Reference thread which comments may be related to a 1950 tube. Any insight or opinions are appreciated. (PIC below)_

 

[Skylab]

What else is there to know? Fabulous tube from the heyday of vacuum tube production. Post-war Sylvania tubes are outstanding (as were the JAN tubes too of course). I use all Sylvania tubes in my Cary SLP-05, and trust me, I tried them all.

 

[Ripper2860]

Need help deciphering a date code on an RCA 6SN7GTB. It's a black plate/single side getter, silver label RCA with date code ACS. Any help in determining year would be appreciated. Also any opinions on this tube.

Thanks.

 

[gibosi]

The GTB was introduced in 1954, so that is the earliest it could have been made. Ring getters were introduced around 1960. You don't say if your tube has a rectangular getter or a ring getter, but that information can help to date the tube. And there is a document available on the web with information regarding RCA date codes:

http://pax-comm.com/rcadates.pdf

On page 18 of the that document, a list of two-letter date codes used between 1956 and 1976 is provided. "AC" would indicate that the tube was packed in a box and shipped out in April, 1964. However, your date code is three letters: "ACS" and I don't know the significance of "S"....

Sorry, I don't own any GTB tubes, so will have to leave impressions to others...

 

[Wes S]

To all,

I have been reading, but can't seem to find enough results to get a good answer.

Is there any sonic difference between the Tung-Sol 6sn7gt (black glass/round plate), with copper grid post or steel grid post?

Thanks,

Wes